What Is Federated Single Sign-On?

In today’s interconnected digital world, users often need to access applications and systems owned by different organisations or domains. Traditional Single Sign-On (SSO) works well within a single enterprise, but when it comes to securely authenticating across multiple domains, Federated Single Sign-On is the solution.

This article explains what federated SSO is, how it works, how it differs from regular SSO, and the role it plays in modern identity and access management.

Federated SSO Explained

Federated Single Sign-On (SSO) is a system that allows users to access multiple applications across different organisations or domains using a single set of login credentials. It enables identity sharing between trusted partners, known as a federation.

In simple terms, federated SSO lets users from one organisation log in to systems belonging to another organisation, without needing to create separate accounts for each one.

This is achieved through trust relationships established between Identity Providers (IdPs) and Service Providers (SPs), using protocols such as SAML (Security Assertion Markup Language) or OpenID Connect.

How Federated SSO Works

Below is the general process for how federated SSO works:

• User requests access to an application (the Service Provider).
• The Service Provider redirects the user to their Identity Provider (IdP).
• The IdP authenticates the user (typically using their organisation's credentials).
• Once authenticated, the IdP sends a secure token or assertion back to the Service Provider.
• The user gains access to the application – without needing to log in again or create a new account.

All of this happens behind the scenes in seconds, allowing for seamless cross-domain access.

Federated SSO vs Standard SSO

Standard SSO provides convenience within your internal systems. Federated SSO extends that convenience to trusted external systems, without compromising on security or user experience.

Common Use Cases for Federated SSO

Federated SSO is widely used in scenarios such as:

• Business-to-business collaboration: Allowing a partner company’s employees to access your services using their own login credentials.
• Educational institutions: Students logging into digital services provided by third parties using university credentials.
• Cloud service access: Logging into SaaS tools (e.g. Salesforce, Microsoft 365) with corporate credentials.
• Public sector services: Government agencies sharing identity infrastructure across departments.

The Role of Identity Federation

Federated SSO is a key component of identity federation, which refers to the arrangement between multiple trusted parties to share authentication responsibilities. It is the trust framework that enables federated SSO to function.

Identity federation allows users to authenticate once with their home organisation and access external services securely – all without the need to manage multiple usernames or passwords.

There are many benefits to federated SSO, including all of the following:

• Improved user experience – users log in once and gain access across systems
• Enhanced security – eliminates the need to manage credentials across different platforms
• Reduced IT overhead – fewer support tickets and password resets
• Stronger B2B collaboration – secure access for partners, vendors, or clients
• Simplified compliance – centralised control of access and identity

Federated Single Sign-On is a powerful solution for enabling secure, seamless access across organisational boundaries. By establishing trusted relationships between identity providers and service providers, federated SSO allows users to access external systems without compromising on security or convenience.

My1Login is an SSO provider which supports federated SSO to help organisations unify identity management across internal and external systems, enabling secure collaboration, streamlined access, and robust compliance.